Directional drilling is commonly used for the drilling of oil and gas wells, as well as for the installation of pipe and other utilities in locations below surface regions where digging cannot occur. For example, the surface may contain wetlands; streams, rivers, or other water bodies; houses, or other things for which it is required or desired to leave them undisturbed. Drilling is performed from surface locations wherein drilling is acceptable, and the drill is guided along the desired path, sometimes to a second surface location, as described in greater detail below.
A typical directional drilling operation for laying pipe underground begins by drilling a pilot hole from a first location. The pilot hole is drilled using a drill string with an asymmetrical leading edge. The asymmetrical leading edge causes the drill to steer towards the “tool face” of the drill, and the drill can be steered by rotating the drill so that the tool face is oriented towards a desired travel direction. If travel in a straight line is desired, rotating the tool face will achieve this result. The tool face includes a hydraulic nozzle for cutting through soil. A probe that is located close to the leading edge sends a signal to the drill operator, informing the drill operator of the location of the drill and other information. The drill can thus be directed underneath a region that must be left undisturbed, and then directed upwards on the other side of that region.
Once the drill re-emerges from the ground, a reamer is attached to the drill, and the hole is reamed to a desired diameter. Reaming is also accomplished through hydraulic cutting. Simultaneously with reaming the hole, the pipe to be installed is pulled into the hole by retracting the drill.
The use of hydraulic cutting creates tremendous hydraulic pressure within the hole, not just from the cutting itself, but throughout the fluid that remains within the hole. This pressure can result in unintended discharges if there are any pre-existing holes or fissures within the soil, leading to fluid and/or mud entering undesirable locations, which could potentially include the very regions that directional drilling is being used to protect. This fluid is preferably extracted during cutting, but present methods of extraction do not relieve sufficient pressure to prevent unintended discharges.
An example of a presently available system is disclosed in U.S. Pat. No. 8,869,915, which discloses a system for sonic subsurface material removal. The system includes an outer tube that is attachable to a drill string. An inner tube is disposed within the outer tube, defining an annular region between the inner and outer tubes. Air, water, or other pressurized fluid can be injected into the borehole through the annular region between the inner tube and the outer tube. As the air, water, or other pressurized fluid goes into the borehole, below the waterline, and then back out through the inside of the inner tube, it carries with it sand or other materials for which removal is desired.
U.S. Pat. No. 6,662,644 discloses a formation fluid sampling and hydraulic testing tool. The sampling device is attached between the drill bit and the drill string. The device includes an outer tube having a plurality of holes, with each of the holes having a filter made from a stainless steel screen. An inner tube is disposed within the outer tube, defining an annular space between the inner and outer tubes. The annular space is sealed from the open ends of the outer tube. The upper end of the inner tube includes a spring biased valve that interfaces with a flanged sleeve. Holes within the flanged sleeve permit communication between the flanged sleeve and the annular space. During a drilling operation, drilling fluid is permitted to pass downward past the valve cone into the inner tube. The drilling fluid then passes through the bottom of the sampling device, driving the drilling bit. During normal drilling, the holes within the flanged sleeve are closed by another sleeve that is pushed downward by pressure from the drilling fluid. To obtain a sample, the flow of drilling fluid is halted. A pump is submerged into the drilling pipe to pump out the drilling fluid. The resulting underpressure raises the sleeve within the flanked sleeve, thereby exposing the holes within the flanged sleeve. The fluids to be sampled enter the annular space between the inner and outer tube through the holes defined within the outer tube. After passing through the annular space, the fluid to be sampled passes through the holes within the flanged sleeve, and can be pumped out of the open upper end of the sampling device.
U.S. Pat. No. 4,448,267 discloses a door drilling Kelly. The device includes a hollow shaft with doors in various positions along its length. The device can be fitted with a lifting bale at its upper end and a cutting bit at its lower end. After the borehole is pre-drilled, the Kelly is placed within the borehole, and an airlift reverse flow system is applied to the inlet or cutting bit. Drilling fluid and cuttings are caused to circulate up the hollow body to the unlatched door. Torque is applied to the Kelly, twisting the cutting bit, so that submerged earth is loosened and lifted to the inlet of the bit, drawn within the Kelly, and transmitted to the unlatched door. Whenever the Kelly is advanced so that the unlatched door approaches the level of the drilling fluid surface, drilling is interrupted, the doors latched, and the next-door is unlatched.
U.S. Pat. No. 7,299,880 discloses a diverter tool having a surge reduction bypass valve. The diverter tool forms part of a running string for running casing down a wellbore, and is disposed between a running pipe and a drill pipe. The diverter tool includes an upper end, a lower end, and a port body therebetween. The upper end includes a flapper body that is closed by pressure from within the diverter tool, and opened downward by pressure from above the diverter tool. The port body includes a plurality of ports for permitting passage of fluid therethrough. A sleeve extends downward from the flapper body, through the port body, and is biased by a spring to a position wherein it blocks the ports. Upward pressure on the flapper body from fluid within the port body causes the sleeve to move, exposing the ports and allowing the fluid to exit the pipe. If injecting fluid into the wellbore, for example, to clear a blockage, is desired, then the flapper is pushed open and the sleeve is pushed over the ports, permitting the fluid to pass through the running string.
U.S. Pat. No. 7,168,492 discloses a wellbore annulus flushing valve. The valve assembly includes a valve disposed within its upper portion that is spring biased into an open position, and which is structured to resist fluid flow traveling upward within the body of the valve assembly, while permitting fluid flow downward. A second valve located within a lower portion of the assembly is structured to resist fluid flow in a downward direction within the body, permitting some downward fluid flow, while permitting upward fluid flow. When the valve assembly is inserted into a wellbore as part of a cleaning string, a cylindrical mandrel holds the upper valve in its open position, and is itself retained in place by sheer pins. During a cleaning operation, fluid is generally permitted to flow upward through the cleaning string. However, if polluting materials such as oil deposits are brought to the surface, then fluid may be pushed downward into the cleaning string. The downward fluid flow closes the lower valve, so that continued downward fluid pressure will break the sheer pins and move the mandrel downward. Moving the mandrel downward enables the upper valve to function, and disables the lower valve. At this point, downward fluid flow will be permitted, but upward fluid flow will be resisted by the upper valve.
U.S. Pat. No. 8,955,599 discloses a system for removing fluids from a subterranean well. The system includes a pump within a horizontal section of the wellbore, and another pump for removing fluid from a vertical section of the wellbore. The fluid is removed through tubing, which may be a multilayer tubing having an outer section, an inner section, and an annulus between the inner and outer sections. Fluid may be separated into wanted portions and unwanted portions. Separation of wanted from unwanted fluids may occur either before or after removal from the wellbore. In some examples, wanted and/or unwanted fluids may be removed through the inner section of the tubing. In other examples, the unwanted fluids are transported to the surface through the annular region of the tubing, with wanted fluids being transported through the inner region of the tubing. The pumps may operate continuously or in response to sensors, and may operate simultaneously or sequentially. A similar device is disclosed in US 2011/0209879.
U.S. Pat. No. 8,733,449 discloses a selectively activatable and deactivatable wellbore pressure isolation device. The system includes a pair of valves that are structured to permit downward fluid flow and resist upward fluid flow. Each of the valves has an associated sleeve which, when positioned over the valve, restricts movement of the valve, permitting fluid flow in both directions. When the system is in the trip in mode, the first sleeve is retained in a position wherein the first valve is activated. The sleeve is maintained in this position by sheer pins, and is structured to be maintained in its other position by a snap-in mechanism. In the trip in mode, the second sleeve is held in a position so that the second valve is deactivated. Like the first sleeve, the second sleeve is held in this position by sheer pins, and in its other position by a snap-in mechanism. To transition the system to its operational mode, the first sleeve is transitioned to its second position to deactivate the first valve. To transition the device to its trip out configuration, the second sleeve is transitioned to its second position, thereby activating the second valve.
U.S. Pat. No. 7,451,828 discloses a downhole pressure containment system. The system includes upper and lower valves with actuators. The valves are selectively openable and closable using hydraulic, pneumatic, or telemetry means. After the bottom valve is closed, a fluid may be placed into the section between the valves. Once the fluid rises above the upper valve, the upper valve may be closed, and additional fluid added until the pressure reaches a predetermined level. Once the pressure reaches this level, the portions of the wellbore above and below the system are isolated, and a tool disposed above the valve may be removed. Some examples also include a downhole tool trap having a catcher flap that is in communication with the actuators for the valves described above.
Thus, although various means of controlling fluid and pressure within a bore during drilling and other operations are disclosed, a means of simultaneously performing a directional drilling operation and removing fluid from the wellbore to reduce pressure within the wellbore is not presently known. The pressure generated during a drilling operation is only useful at the location wherein drilling is actually occurring. Behind this location, such pressure only creates a risk that mud and fluid will exit through any areas of weakness that may exist in the surrounding soil, raising environmental concerns and resulting expenses. A tool which can be attached to a drill during a drilling or pipe installation operation, performing the fluid and mud removal function simultaneously with the drilling or installation operation, is therefore highly desirable to reduce the risk of unintended discharge.
Accordingly, there is a need for a mud and fluid extraction device and method that removes directional drilling byproducts with sufficient effectiveness to resist a buildup of pressure that could lead to unintended discharges. There is an additional need for a mud and fluid extraction device and method that leaves sufficient pressure at the tool face of the drill for effective cutting while relieving pressure behind the tool face. There is a further need for a device and method of mud and fluid extraction that can be incorporated into existing directional drilling equipment. Additionally, there is a need for a device and method of mud and fluid extraction that does not overcomplicate the directional drilling process, and which can be accomplished during the present directional drilling process.